Anti-metastatics: an overview of drug candidates in current pipelines

Genome-wide analysis of canine oral malignant melanoma metastasis-associated gene expression

Oral malignant melanoma (OMM) is the most common canine melanocytic neoplasm. Overlap between the somatic mutation profiles of canine OMM and human mucosal melanomas suggest a shared UV-independent molecular aetiology. In common with human mucosal melanomas, most canine OMM metastasise. There is no reliable means of predicting canine OMM metastasis, and systemic therapies for metastatic disease are largely palliative. Herein, we employed exon microarrays for comparative expression profiling of FFPE biopsies of 18 primary canine OMM that metastasised and 10 primary OMM that did not metastasise. Genes displaying metastasis-associated expression may be targets for anti-metastasis treatments, and biomarkers of OMM metastasis. Reduced expression of CXCL12 in the metastasising OMMs implies that the CXCR4/CXCL12 axis may be involved in OMM metastasis. Increased expression of APOBEC3A in the metastasising OMMs may indicate APOBEC3A-induced double-strand DNA breaks and pro-metastatic hypermutation. DNA double strand breakage triggers the DNA damage response network and two Fanconi anaemia DNA repair pathway members showed elevated expression in the metastasising OMMs. Cross-validation was employed to test a Linear Discriminant Analysis classifier based upon the RT-qPCR-measured expression levels of CXCL12, APOBEC3A and RPL29. Classification accuracies of 94% (metastasising OMMs) and 86% (non-metastasising OMMs) were estimated.

Re-Use of Established Drugs for Anti-Metastatic Indications

Most patients that die from cancer do not die due to the primary tumor but due to the development of metastases. However, there is currently still no drug on the market that specifically addresses and inhibits metastasis formation. This lack was, in the past, largely due to the lack of appropriate screening models, but recent developments have established such models and have provided evidence that tumor cell migration works as a surrogate for metastasis formation. Herein we deliver on several examples a rationale for not only testing novel cancer drugs by use of these screening assays, but also reconsider established drugs even of other fields of indication.

Targeting metastatic breast cancer: problems and potential

Breast cancer is one of the leading causes of cancer-related mortality of women in the United States. Since the majority of cancer deaths are due to metastases rather than the primary tumor, a better understanding of the biological mechanisms that lead to metastatic disease is critical to reduce breast cancer associated mortality. Current adjuvant therapies use the same broadly cytotoxic and targeted strategies against metastases as are used against the primary tumor. However, resistance to chemotherapy due to the cellular dormancy, high genotypic and phenotypic heterogeneity between primary tumor and metastases as well as among individual metastases, and the limitations in detection of disseminated tumor cells and micrometastases significantly hinder the efficiency of currently available therapies. While it is crucial to directly address the issue of metastatic dormancy and evaluate for anti-metastatic therapy the relevance of molecular targets chosen based on primary tumor profiling, it is also imperative to address metastasis-specific mechanisms of growth and survival that are likely to be distinct from those of the primary tumor. We believe that a three-pronged approach to therapy will be necessary to deal with progressive disease: blocking of further dissemination after diagnosis; eradication of disseminated tumor cells and prevention of the dormant-to-proliferative switch of those remaining; and elimination of established metastatic tumors. The implementation of this strategy requires a greater depth of knowledge of metastasis driver and maintenance genes and suggests the need for a "Metastasis Genome Atlas" project to complement the current investigations into cancer genomic landscapes.